This application claims priority to German application Nos. 199 03 490.7 (now German Patent DE 199 03 490) and 299 01 516.5, both of which were filed on Jan. 29, 1999.
The invention relates to a position device for a throttle valve that contains at least an angular rotation sensor unit and a control unit that is arranged on the throttle valve element, and more particularly the invention relates to a device wherein the throttle valve with a throttle valve shaft element is arranged in a housing element, so that it can be adjusted.
A position device of the aforementioned type is known from WO 95 14 911 A1. In that reference, which discloses an enclosed throttle valve housing, a throttle valve with a throttle valve shaft is arranged so that it may rotate. An angular rotation sensor, which consists of a stationary and a rotating unit, is connected to the throttle valve shaft. In a stator element of the stationary unit, a Hall-effect element is arranged. The rotating unit features a ring magnet that can be moved around the stator element. This angular rotation sensor is, however, arranged in a cup-shaped housing and placed on the throttle valve housing from the outside.
In the event that a motor unit and a transmission unit are used as a drive unit, they are placed in the actuator housing together with the angular rotation sensor and a circuit unit. The actuator housing is then placed on the throttle housing. In both cases it is visible from the outside that the throttle valve housing has been fitted with accessories. In addition, dirt, etc., can build up, particularly between the throttle valve housing and the actuator housing.
DE 197 13 838 A1 discloses a throttle valve potentiometer. In that reference, a positioning motor that acts upon a throttle valve shaft via a reducing gear transmission is installed in or attached to a throttle valve housing. A carrier plate is glued into the throttle valve housing. The carrier plate carries contact rails and/or sliding contacts, wherein a collector, which is positioned on the throttle valve shaft, slides over the rails. The carrier plate, the contact rails and/or sliding contacts as well as the collector form the throttle valve potentiometer.
It is a disadvantage that the throttle valve potentiometer can only be constructed and assembled in one place together with the throttle unit. In addition, the insertion of the potentiometer is time intensive and complex.
Additionally, adjusting devices are known, for example, from 95 14 911 A1, which discloses a throttle valve contained in a throttle valve housing. The throttle valve is retained rotatably in the throttle valve housing by a throttle valve shaft. An angular rotation sensor, a transmission unit, and a motor unit that are connected to each other are contained in a sensor housing. A specially configured electronics housing separately contains a circuit unit. The individual housing elements can be plugged together. The angular rotation sensor consists of a stationary component in relation to which a rotatable component can be moved. The stationary element is a stator element consisting of two half-moon-shaped partial stator elements between which a distancing gap is located that retains a Hall probe. The rotating element is a ring magnet element that is retained by a magnet unit connected by a shaft.
Although this adjusting device is a proven design, the assembly effort is still too high. In addition, the angular rotation sensor, the motor, and the transmission cannot be attached to any throttle unit.
The present invention is directed to a position device for a throttle of the aforementioned type in such a way that the assembly with the throttle valve housing and the throttle valve shaft is easier and more cost effective to manufacture.
The advantages accomplished by the invention consist mainly in that the active elements of the angular rotation sensor are contained in a cap element. In addition, depending on the requirements, a motor may also be installed in the cap element as a control unit. The control unit and the rotor element of the angular rotation sensor are connected via a transmission. In an exemplary embodiment, the chosen gear ratio is 1:200. This ratio makes sure that even the smallest movements of the throttle valve are registered precisely. Due to the slip-free transmission, the precision of the registered values is extremely high. It is a particular advantage of the present invention that the cap element and the parts contained in it can be manufactured separately in large quantities. This reduces manufacturing costs significantly. The cap element itself may be adapted to the individual throttle valve housings. If necessary, an adapter may be used. Since it is rather easy to put the cap element on the throttle valve housing element, assembly costs are also reduced. Once the throttle valve housing element has been closed with the cap element, a unit is formed that, when viewed from the outside, is visibly finished.
In a broad aspect, the present invention also comprises an adjusting device including: a throttle unit comprising a throttle valve that is positioned adjustably with a throttle shaft in a throttle housing element; and an angular rotation sensor unit that can be connected with the throttle unit and that comprises a stationary unit, a mobile unit that is mobile in relation to the stationary unit, a motor element, a transmission element that is positioned between the mobile unit and the motor element, and a sensor housing unit that at least partially encloses at least the stationary unit, the mobile unit, the motor element, and the transmission unit.
Accordingly, it is an object of the present invention to provide an adjusting device which is easy to assemble and to attach to a throttle unit.
The advantages resulting from the invention consist mainly in that the mobile unit can be moved into a defined end position by a spring element. This end position assists both in assembly and in positioning. Installing the mobile unit in a sprocket wheel that is part of the transmission unit saves space and simplifies assembly. Assembly is further simplified by positioning certain components inside the sensor cap element and inside the sensor housing element. By putting the sensor cap element on the sensor housing element simultaneously, the mobile unit is fixed and assembled on the stationary unit. In addition, the angular rotation sensor unit with the transmission may be plugged onto any throttle unit in a simple manner.
The stationary unit and the mobile unit may be part of a potentiometer angular rotation sensor or of an angular rotation sensor unit that functions based on a magneto-electrical principle: which of the principles is applied depends on the deployment conditions and on the requirements of the customer.
In the angular rotation sensor unit, the stationary unit may be a stator element with at least one Hall probe and one correlated circuit board. The mobile unit may be a rotor element with at least one ring magnet element that is retained by a ring magnet retaining element and that may be moved in relation to the stator element. This makes it possible to measure the rotation angle with utmost precision.
The stator element comprises at least two partial stator elements between which a distancing gap exists, so that the elements may be inserted into a stator-retaining recess of the sensor cap element. This permits assembly of the stator element in the proper position.
Two Hall probes may be positioned on the circuit board. There are two Hall probes for reasons of redundancy. This significantly increases the reliability of the angular rotation sensor unit. The circuit board may be attached inside the sensor cap element in such a manner that the two Hall probes are located in the distancing gap. This measure reduces to a minimum the adjusting effort for the precise fixing of the two Hall probes in the distancing gap.
The transmission unit may comprise: a rotor sprocket wheel into which the ring magnet retaining element with the ring magnet element of the rotor element is embedded as a rotating unit, and to which a sensor shaft element may be connected; an adjustable sprocket wheel into which the rotor sprocket wheel engages, and with which an intermediate sprocket wheel interfaces; and a motor sprocket wheel that may be connected to a shaft of the motor element.
Through the gear ratio of the individual rotations of the motor element and, above all, of the rotating unit, minute changes caused by these parts are effectively registered and precisely transferred.
The sensor shaft element may be at least partially slotted. The provisioned slot in the sensor shaft element guarantees that the entire angular rotation sensor unit is correctly plugged onto differing throttle units. In this way, special adjustments or complicated assembly are avoided.
The rotor sprocket wheel may contain a stop recess into which a stop element can be positioned. In this manner, it is guaranteed that the rotor element is always rotated back by the spring element into a defined position. The spring element may be a torsion spring.
A peripheral cap gasket element may be located between the sensor cap element and the sensor housing element. The cap gasket element may be made from a flexible gasket material such as rubber, soft plastic material, or a similar material. The gasket ensures that the interior of the thus created sensor housing unit is effectively protected from dust, humidity, and the like.